This invention relates to blending reclaimed rubber elements with tread rubber to produce a rubber product for tire retreading. In particular the invention is concerned with blending rubber buffing dust with ribbon tread rubber whereby there is obtained a rubber extended strip product for winding on a tire casing.
During retreading procedures the casing of a tire which is to be retreaded undergoes processes which generates substantial rubber waste in the form of rubber dust or buffing dust. Conventionally such buffing dust has been discarded or wasted, but in current times where recycling of previously wasted products now is economically important, it is desirable to reuse such dust if possible.
Processes for reusing reclaimed rubber waste have long been known, but the applicant is unaware of any process for effectively reusing the buffing dust by effectively blending tread rubber, which is commercially supplied for retreading tire casings, and the buffing dust so as to provide a desirable rubber product for tire retreading.
Retreading units and machines include, for instance, the Orbitread machine (Registered Trademark) produced by the AMF Corporation. In such a machine tread rubber in ribbon form is fed into a hopper and is then extruded through a extruder screw operating in a barrel so as to be discharged in a strip form which can then be wound about a buffed casing mounted on a rotatable shaft. Prior to the rewinding or retreading process the casing is buffed to remove excess rubber, and it is this excess rubber which has conventionally been wasted.
There is accordingly a need to provide an effective means for recycling this buffed rubber dust and effectively blending this dust into the tread rubber such that the rubber for retreading is a useful, high-quality end product, whereby retreading can be less expensive than by retreading with the tread rubber alone.